The charge-density visualizations shown at the bottom of Fig. REF  demonstrate the atoms that contribute to the states at \(E_F\) . Not surprisingly, the transition metals show greater affinity towards oxygen and the metal-oxygen (\(M-O\)  = 1.9 Å) bond length (only in oxygen-passivated cases) is \(\sim 10 \%\)  lesser than that of metal-nitrogen (\(M-N\) ) and metal-fluorine (\(M-F\) ) bond lengths. On the other hand, due to \(O-H\)  bonding in \(Mn_2N(OH)_2\) , the \(M-O\)  bond length is increased and equals (\(\sim \)  2.1 Å) to that of \(M-N\)  and \(M-F\) . Usually, the states that arise due to \(M-O\)  coordinated covalent interaction are more dispersed as happens in many transtion metal oxides [1]}. However, the disorders in the system (in the form of structural/chemical) would make the states localized [1]}, [3]}. The localization in the present case occurs due to dimensional confinement imposed on the \(p\) -electrons of terminating oxygens. Nevertheless, whenever the \(N(p)-M(d)\)  covalent interaction is predominant, the geometrical position of \(N\)  allows the \(N(p)\)  electrons to move freely in all three directions and the states are found to be relatively dispersive. The \(N(p)-M(d)\)  hybridized states at \(E_F\)  are formed in the absence of oxygen surface group. In oxygen-passivated systems, the \(N(p)-M(d)\)  hybridized states are found deep in the valence and conduction band energy (see Fig. REF ) and the weakly dispersive \(O(p)-M(d)\)  hybridized states at \(E_F\)  hold the accountability for larger AHC in \(M_2NO_2\) .
